Communication systems of various kinds, including wireless communication systems, are known. In many cases such communication systems support the conveyance of data, often by employing packetized services. For various reasons (relating sometimes to the nature of the service itself and sometimes to an anecdotal context) the quantity of data to be transmitted to or by a given system participant can and will vary widely. For example, in a typical wireless communication system, file sizes can readily vary in size from 0.5 KB or smaller to 1 MB and larger. The amount of time required to successfully convey such data will therefore usually vary as well. For example, when the wireless channel supports an 8 KBPS data rate, roughly 500 milliseconds are required to transmit a 0.5 KB file while roughly 1,000 seconds are required to transmit a 1 MB file. (Faster effective data rates will reduce these numbers, but a differential spread will still persist. For example, when a wireless channel supports a 40 KBPS data rate, the 0.5 KB file will typically require roughly 100 milliseconds and the 1 MB file will require roughly 200 seconds.)
Reception conditions in a wireless system can vary greatly over time and with respect to location (other factors can also play a part). Some communication systems have an ability to make a dynamic selection of a particular data rate to use when supporting the conveyance of data. One particularly successful example is found at US 2002/0147022 entitled Method for good Packet Scheduling and Radio Resource Allocation in a Wireless Communication System (the contents of which are incorporated herein by this reference). This approach permits a fairness parameter β to be employed. Generally speaking, this approach provides for the detection of radio frequency resource usage and a given data rate is then increased or decreased as a function of determined resource requirements in an attempt to achieve a fairer balance of services.
For example, the data rate in a given instance will typically be increased when assigned to communications that require less power, Walsh Code legs, or other relevant communication resource (with respect to a reference). The fairness parameter β can be varied (by a system administrator, for example) to influence the amount by which a data rate increases or decreases in this manner. In effect, this permits a system administrator to influence the extent to which communications units experiencing poor channel conditions receive correspondingly reduced data rates in order to increase total effective system throughput.
More particularly, the above-described approach uses both an instantaneous radio frequency environment measure and a radio frequency environment average over a longer time scale (typically influenced by a time scale factor □) to determine the data rate to be assigned. As a result, when the instantaneous radio frequency environment is poor but the longer-term average is good, a reduced data rate will typically be assigned due to an increased likelihood that the radio frequency environment will improve in the near future. When, however, the instantaneous radio frequency is poor and the longer-term average is also poor, then a more normal data rate will typically be assigned because it is less likely that the radio frequency environment will improve anytime soon. (Note: A smaller □ (closer to 0) implies a longer/larger time-scale and a larger □ (closer to 1) implies a shorter/smaller time-scale.)
This prior art approach in fact works well for many applications and under many operational circumstances. There are situations, however, when this approach can yield less than optimal results. For example, when applying this approach, communications involving only a relatively small quantity of data may be unduly impacted. Since larger files typically require a commensurately longer period of time to effect their complete transmission, this prior art approach works quite well. Smaller files, however, typically entail a shorter file transfer time. As a result, the above approach, with its reliance upon a long-term average analysis, can unduly skew data rate allocation in a way that can adversely impact such transactions.
In particular, a reduced data rate can be assigned to facilitate the transmission of a small data file based upon a presumption that channel conditions will improve in the near future and therefore likely permit a subsequent up tick in the applied data rate. Because of the small size of the data file, however, the data communication will often be completed before such improvement to channel conditions occurs. As a result, the entire transaction is burdened by application of an intentionally reduced data rate.